Scroll compressor

ABSTRACT

A scroll compressor prevents shortage of lubrication for sliding portions of a scroll unit. A scroll compressor 10 includes: an oil separator 100 that separates lubricant from the gaseous refrigerant discharged into a discharge chamber H3; a first lubricant chamber H5 that stores the lubricant separated by the oil separator 100; a first lubricant supply passage for supplying the lubricant in the first lubricant chamber H5 to a back pressure chamber H6; and a second lubricant supply passage for supplying the lubricant in the first lubricant chamber to a portion near an outer end portion of a scroll unit 50. The second lubricant supply passage is formed as a passage that allows the lubricant in the first lubricant chamber to flow through a second lubricant chamber H7 disposed above the first lubricant chamber H5 and connected to the first lubricant chamber H5 via an orifice OL3.

TECHNICAL FIELD

The present invention relates to a scroll compressor that is, for example, used in an air conditioner for a vehicle.

BACKGROUND ART

Patent Document 1 describes an example of this kind of scroll compressor. The scroll compressor described in Patent Document 1 includes a scroll unit having a fixed scroll and an orbiting scroll, a discharge chamber into which gaseous refrigerant compressed by the scroll unit is discharged, a back pressure chamber that has a back pressure that presses the orbiting scroll to the fixed scroll, an oil separator that separates lubricant from the gaseous refrigerant compressed by the scroll unit, and a back pressure supply passage for supplying the lubricant separated by the oil separator to the back pressure chamber.

REFERENCE DOCUMENT LIST Patent Document

Patent Document 1: JP 2018-159285 A

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

In the case of a conventional scroll compressor, lubrication of various sliding portions is achieved mainly by lubricant contained in the gaseous refrigerant. However, for example, when the performance or reduction in size of scroll compressors advances, a sufficient amount of lubricant may not be contained in the gaseous refrigerant, and as a result, in particular, lubrication of sliding portions of a scroll unit may become insufficient.

Thus, it is an object of the present invention to provide a scroll compressor that prevents shortage of lubrication for sliding portions of a scroll unit.

Means for Solving the Problem

In an aspect of the present invention, a scroll compressor is provided. This scroll compressor has a housing in which are disposed a scroll unit including a fixed scroll and an orbiting scroll that face each other. The housing includes a discharge chamber into which gaseous refrigerant compressed by the scroll unit is discharged. In addition, the scroll compressor includes: an oil separator that separates lubricant from the gaseous refrigerant discharged into the discharge chamber; a first lubricant chamber that stores the lubricant separated by the oil separator; a back pressure chamber that is formed on the back surface side of the orbiting scroll; a first lubricant supply passage for supplying the lubricant in the first lubricant chamber to the back pressure chamber; and a second lubricant supply passage for supplying the lubricant in the first lubricant chamber to a portion near an outer end portion of the scroll unit. The second lubricant supply passage is formed as a passage that allows the lubricant in the first lubricant chamber to flow through the second lubricant chamber disposed above and connected to the first lubricant chamber via an orifice.

Effects of the Invention

According to the present invention, there is provided a scroll compressor that prevents shortage of lubrication for sliding portions of a scroll unit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view illustrating a schematic structure of a scroll compressor according to an example embodiment of the present invention.

FIG. 2 is a sectional view taken along a line A-A in FIG. 1 .

FIG. 3 is a block diagram illustrating how gaseous refrigerant and lubricant flow in the scroll compressor.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an example embodiment of the present invention will be described based on the accompanying drawings.

FIG. 1 is a sectional view illustrating a schematic structure of a scroll compressor 10 according to an example embodiment of the present invention. The scroll compressor 10 according to this example embodiment is incorporated in a refrigerant circuit, for example, in an air conditioner for a vehicle. Upon receiving low-pressure gaseous refrigerant from the refrigerant circuit, the scroll compressor 10 compresses this low-pressure gaseous refrigerant into high-pressure gaseous refrigerant, and returns the high-pressure gaseous refrigerant to the refrigerant circuit. The left side in FIG. 1 is the front side of the scroll compressor 10, and the right side in FIG. 1 is the rear side of the scroll compressor 10. In addition, the upper side in FIG. 1 is the upper side of the scroll compressor 10, and the lower side in FIG. 1 is the lower side of the scroll compressor 10.

The scroll compressor 10 includes a housing 20, a rotary shaft 30, an electric motor 40 that rotates the rotary shaft 30, a scroll unit 50 that is driven by the rotary shaft 30 and compresses the (low-pressure) gaseous refrigerant, and an inverter 60 that drives and controls the electric motor 40. The rotary shaft 30, the electric motor 40, the scroll unit 50, and the inverter 60 are stored in the housing 20. In addition, the scroll unit 50 includes a fixed scroll 51 and an orbiting scroll 52 that orbits with respect to the fixed scroll 51.

The housing 20 includes a front housing 21, a cover member 22, a center housing 23, and a rear housing 24. The housing 20 of the scroll compressor 10 is formed by fastening the above housing members to each other with fastening members (not shown), for example.

The front housing 21 has a cylindrical peripheral wall portion (hereinafter referred to as a “first peripheral wall portion”) 211 that extends in the longitudinal direction of the scroll compressor 10 and a partition wall portion (hereinafter referred to as a “first partition wall portion”) 212 that partitions the inside of the first peripheral wall portion 211 into front and rear portions. The front end surface of the first peripheral wall portion 211 constitutes the front end surface of the front housing 21, and the rear end surface of the first peripheral wall portion 211 constitutes the rear end surface of the front housing 21. In the present example embodiment, the inside of the first peripheral wall portion 211 (that is, the internal space of the front housing 21) is partitioned by the first partition wall portion 212 into a front-side inverter storage space storing the inverter 60 and a rear-side motor storage space storing the electric motor 40. That is, the electric motor and the inverter 60 are stored in the front housing 21.

The first partition wall portion 212 has a supporting portion 213 that supports the front end portion of the rotary shaft 30. Specifically, in the present example embodiment, the supporting portion 213 is formed to protrude in a cylindrical shape into the motor storage space from the rear side surface of the first partition wall portion 212. The supporting portion 213 rotatably supports the front end portion of the rotary shaft 30 via a first bearing 214 mounted inside the supporting portion 213.

The cover member 22 is bonded to the front end surface of the front housing 21. In this way, the inverter storage space is covered (an inverter storage chamber is formed). The rear end surface of the front housing 21 is bonded to the front end surface of the center housing 23. A sealing member may be disposed between the front housing 21 and the cover member 22 and between the front housing 21 and the center housing 23, as necessary.

The center housing 23 has a cylindrical peripheral wall portion (hereinafter referred to as a “second peripheral wall portion”) 231 that extends in the longitudinal direction and a partition wall portion (hereinafter referred to as a “second partition wall portion”) 232 that partitions the inside of the second peripheral wall portion 231 into front and rear portions. The front end surface of the second peripheral wall portion 231 constitutes the front end surface of the center housing 23, and the rear end surface of the second peripheral wall portion 231 constitutes the rear end surface of the center housing 23. In the present example embodiment, the inside of the second peripheral wall portion 231 (that is, the internal space of the center housing 23) is partitioned by the second partition wall portion 232 into a front-side connection space that connects to the motor storage space of the front housing 21 and a rear-side scroll storage space that stores the scroll unit 50. That is, the scroll unit 50 is stored in the center housing 23.

The second partition wall portion 232 has a hollow projection portion 233 that protrudes into the front housing 21 (the motor storage space). The hollow projection portion 233 is formed at a radially center portion of the second partition wall portion 232 so as to face the supporting portion 213 formed on the first partition wall portion 212 of the front housing 21. The top portion of the hollow projection portion 233 has an insertion hole 234 that penetrates the hollow projection portion 233 and into which the rear end portion of the rotary shaft 30 is inserted. In addition, a second bearing 235 that rotatably supports the rear end portion of the rotary shaft 30 is attached to the inside of the hollow projection portion 233. That is, in the present example embodiment, the rotary shaft 30 is rotatably supported by the first bearing 214 formed in the front housing 21 and the second bearing 235 formed in the center housing 23.

The rear end surface of the center housing 23 is bonded to the front end surface of the rear housing 24. In the present example embodiment, a concave portion 236 for storing the outer edge portion of a fixed plate 511 (described below) of the fixed scroll 51 of the scroll unit 50 is formed on the rear end surface of the center housing 23, that is, the rear end surface of the second peripheral wall portion 231. The outer edge portion of the fixed plate 511 of the fixed scroll 51 is sandwiched by the center housing 23 and the rear housing 24. In this way, the fixed scroll 51 is fixed, and the rear side opening of the second peripheral wall portion 231 is covered by the fixed plate 511 of the fixed scroll 51. A sealing member may be disposed between the center housing 23 and the rear housing 24, as needed.

The rear housing 24 has a cylindrical shape with a bottom portion. Specifically, the rear housing 24 has a cylindrical peripheral wall portion (hereinafter referred to as “third peripheral wall portion”) 241 that extends in the longitudinal direction, and has a bottom wall portion 242 that covers the rear side opening of the third peripheral wall portion 241. The front end surface of the third peripheral wall portion 241 that constitutes the front end surface of the rear housing 24 is bonded to the rear end surface of the second peripheral wall portion 231 that constitutes the rear end surface of the center housing 23. In this way, the front side opening of the third peripheral wall portion 241 is covered by the fixed plate 511 of the fixed scroll 51.

The electric motor 40 is, for example, a three-phase alternating current motor, and includes a stator core unit 41 and a rotor 42.

The stator core unit 41 is fixed to the inner periphery of the first peripheral wall portion 211 of the front housing 21. The inverter 60 converts a direct current from, for example, an on-board battery (not shown) into an alternating current, and supplies this alternating current to the stator core unit 41.

The rotor 42 is disposed radially inside the stator core unit 41 with a predetermined gap therebetween. The rotor 42 includes a permanent magnet. The rotor 42 has a cylindrical shape and has a hollow portion into which the rotary shaft 30 is inserted. The rotor 42 is fixed to the rotary shaft 30 in this state. That is, the rotor 42 and the rotary shaft 30 are integrally formed.

When the inverter 60 supplies power to the electric motor 40, a magnetic field is generated in the stator core unit 41. Accordingly, rotary power is applied to the permanent magnet of the rotor 42, and the rotor 42 rotates. As a result, the rotary shaft 30 rotates.

As described above, the scroll unit 50 includes the fixed scroll 51 and the orbiting scroll 52 that orbits with respect to the fixed scroll 51.

The fixed scroll 51 has a discoid fixed plate 511 and a fixed spiral wall 512 erected on one surface of the fixed plate 511. The fixed spiral wall 512 extends in a spiral shape (in the shape of an involute curve) from a radially inner end portion (a spiral start portion) to a radially outer end portion (a spiral end portion) on the one surface of the fixed plate 511. In addition, in a state in which the one surface (the surface on which the fixed spiral wall 512 is erected) of the fixed plate 511 of the fixed scroll 51 faces forward, the outer edge portion of the fixed plate 511 is fixedly sandwiched by the center housing 23 and the rear housing 24.

The orbiting scroll 52 has a discoid orbiting plate 521 and an orbiting spiral wall 522 erected on one surface of the orbiting plate 521. The orbiting spiral wall 522 extends in a spiral shape (in the shape of an involute curve) from a radially inner end portion (a spiral start portion) to a radially outer end portion (a spiral end portion) on the one surface of the orbiting plate 521. In addition, the orbiting scroll 52 is disposed such that the orbiting spiral wall 522 engages with the fixed spiral wall 512 of the fixed scroll 51. That is, the orbiting scroll 52 is disposed between the second partition wall portion 232 of the center housing 23 and the fixed scroll 51, and the one surface of the orbiting plate 521 (the surface on which the orbiting spiral wall 522 is erected) faces backward.

The orbiting scroll 52 is driven by the rotary shaft 30 via a crank mechanism 70 and is constructed to orbit with respect to the fixed scroll 51, in other words, orbit the shaft center of the fixed scroll 51. The orbiting scroll 52 is prevented from spinning by a spin prevention mechanism (not shown).

The scroll unit 50 is configured to draw and compress the low-pressure gaseous refrigerant due to the orbiting motion of the orbiting scroll 52 with respect to the fixed scroll 51. A thrust plate 80 having an annular disk shape is disposed between the orbiting plate 521 of the orbiting scroll 52 and the second partition wall portion 232 of the center housing 23. The rear side surface of the second partition wall portion 232 is constructed to receive the thrust force from the orbiting scroll 52 via the thrust plate 80.

The crank mechanism 70 couples the rotary shaft 30 with the orbiting scroll 52 and converts the rotary motion of the rotary shaft 30 into the orbiting motion of the orbiting scroll 52. In the present example embodiment, the crank mechanism 70 is disposed inside the hollow projection portion 233 of the second partition wall portion 232 of the center housing 23. The crank mechanism 70 includes a crankpin 71 erected on the rear end portion of the rotary shaft 30, an eccentric bush 72 attached eccentrically to the crankpin 71, and a cylindrical portion 73 formed to protrude on the other surface of the orbiting plate 521 of the orbiting scroll 52. The eccentric bush 72 is rotatably supported on the inner periphery of the cylindrical portion 73 via a bearing (not shown). In addition, a balancer weight 74 that counteracts the centrifugal force generated by the orbiting motion of the orbiting scroll 52 is attached to the rear end portion of the rotary shaft 30.

In the present example embodiment, the scroll compressor 10 includes an intake chamber H1 into which the low-pressure gaseous refrigerant flows, a compression chamber H2 in which the low-pressure gaseous refrigerant is compressed, a discharge chamber H3 into which the gaseous refrigerant compressed in the compression chamber H2 is discharged, a gas-liquid separation chamber H4 in which lubricant is separated from the gaseous refrigerant compressed in the compression chamber H2, a first lubricant chamber H5, a back pressure chamber H6 formed on the back surface side of the orbiting scroll 52 (on the other surface of the orbiting plate 521), and a second lubricant chamber H7. FIG. 2 is a sectional view taken along a line A-A in FIG. 1 . In FIG. 2 , the region of the discharge chamber H3 is indicated by a dashed-double dotted line, for illustration purposes.

The intake chamber H1 is a compartment formed by the first peripheral wall portion 211 of the front housing 21, the first partition wall portion 212 of the front housing 21, the second peripheral wall portion 231 of the center housing 23, and the second partition wall portion 232 of the center housing 23. That is, in the present example embodiment, the intake chamber H1 is formed by the motor storage space of the front housing 21 and the connection section of the center housing 23. An intake port P1 is formed in the first peripheral wall portion 211. The intake port P1 is connected to (the low pressure side of) the refrigerant circuit via, for example, a connection pipe (not shown). Thus, low-pressure refrigerant flows from the refrigerant circuit into the intake chamber H1 via the intake port P1. In addition, the center housing 23 includes a refrigerant passage L1 for guiding the low-pressure gaseous refrigerant in the intake chamber H1 to a space H8 near an outer end portion of the scroll unit 50.

The compression chamber H2 is formed in the scroll unit 50, that is, between the fixed scroll 51 and the orbiting scroll 52. Specifically, when the orbiting scroll 52 of the scroll unit 50 orbits with respect to the fixed scroll 51, a crescentic enclosed space is formed by the fixed plate 511, the fixed spiral wall 512, the orbiting plate 521, and the orbiting spiral wall 522 at a radially outer portion, and this crescentic enclosed space formed moves to a radially inner portion as it gradually decreases its capacity. This crescentic enclosed space formed between the fixed scroll 51 and the orbiting scroll 52 constitutes the compression chamber H2. When the crescentic enclosed space (that is, the compression chamber H2) is formed, the scroll unit 50 draws the low-pressure gaseous refrigerant from the space H8 and compresses the drawn low-pressure gaseous refrigerant.

The discharge chamber H3 is formed by the third peripheral wall portion 241 of the rear housing 24, the bottom wall portion 242 of the rear housing 24, and the fixed plate 511 of the fixed scroll 51. That is, the inside of the third peripheral wall portion 241 of the rear housing 24 constitutes the discharge chamber H3. A discharge hole L2 is formed in a radially center portion of the fixed plate 511 of the fixed scroll 51. This discharge hole L2 communicates with the compression chamber H2 that has moved to the innermost portion (that has reached its minimum capacity) and the discharge chamber H3. Thus, the gaseous refrigerant compressed in the compression chamber H2 of the scroll unit 50 is discharged into the discharge chamber H3 via the discharge hole L2. A check valve 90, e.g., a reed valve, is attached to the other surface of the fixed plate 511 of the fixed scroll 51, the other surface being seen from the discharge chamber H3. This check valve 90 allows flow of the gaseous refrigerant from the compression chamber H2 to the discharge chamber H3, but regulates flow of the gaseous refrigerant from the discharge chamber H3 to the compression chamber H2.

The gas-liquid separation chamber H4 is formed in the rear housing 24. Specifically, in the present example embodiment, the gas-liquid separation chamber H4 is formed as a cylindrical space that extends downward from an outer peripheral surface of the bottom wall portion 242 of the rear housing 24 to the inside. The gas-liquid separation chamber H4 includes an oil separator 100 that separates lubricant from the gaseous refrigerant. Although a centrifugal oil separator is used in the present example embodiment, a different kind of oil separator may alternatively be used. A discharge port P2 is formed above the oil separator 100 in the gas-liquid separation chamber H4. The discharge port P2 is connected to (the high pressure side of) the refrigerant circuit via, for example, a connection pipe (not shown). In addition, a communication hole L3 that communicates with the discharge chamber H3 and the gas-liquid separation chamber H4 is formed in the bottom wall portion 242 of the rear housing 24.

Thus, the gaseous refrigerant in the discharge chamber H3, that is, the gaseous refrigerant (the high-pressure gaseous refrigerant) compressed in the compression chamber H2, flows into the gas-liquid separation chamber H4 via the communication hole L3. Next, lubricant is separated from the gaseous refrigerant by the oil separator 100, and the gaseous refrigerant is finally guided to the high pressure side of the refrigerant circuit through the discharge port P2. In addition, the lubricant separated from the high-pressure gaseous refrigerant by the oil separator 100 is guided to the bottom portion of the gas-liquid separation chamber H4 by gravity.

The first lubricant chamber H5 is formed in the rear housing 24. Specifically, in the present example embodiment, the first lubricant chamber H5 is formed when (the opening of) a concave portion formed at the front end surface of the third peripheral wall portion 241 of the rear housing 24 is covered by the fixed plate 511 of the fixed scroll 51. That is, the first lubricant chamber H5 is formed by the fixed scroll 51 and the rear housing 24. The first lubricant chamber H5 is formed below the discharge chamber H3. In addition, a connection passage L4 that connects the bottom portion of the gas-liquid separation chamber H4 and the first lubricant chamber H5 is formed in the rear housing 24.

Thus, the lubricant (including the lubricant temporarily stored on the bottom portion of the gas-liquid separation chamber H4) separated from the high-pressure gaseous refrigerant by the oil separator 100 in the gas-liquid separation chamber H4 flows to the first lubricant chamber H5 via the connection passage L4 and is stored in the first lubricant chamber H5.

The back pressure chamber H6 is formed between the orbiting plate 521 of the orbiting scroll 52 and the second partition wall portion 232 of the center housing 23. In the present example embodiment, the back pressure chamber H6 includes the internal space of the hollow projection portion 233 of the second partition wall portion 232. A lubricant passage L5 that connects the back pressure chamber H6 and the first lubricant chamber H5 is formed in the center housing 23 and the fixed plate 511 of the fixed scroll 51. A first orifice (a first restriction portion) OL1 is disposed in the lubricant passage L5.

In addition, the back pressure chamber H6 communicates with the intake chamber H1 via a pressure release passage L6. In the present example embodiment, the pressure release passage L6 is formed as a passage that runs through the rotary shaft 30 in an axial direction and that passes by the first bearing 214. A second orifice (a second restriction portion) OL2 is disposed in the pressure release passage L6, for example, at the front end portion of the rotary shaft 30.

The second lubricant chamber H7 is formed in the rear housing 24, as is the case with the first lubricant chamber H5. Specifically, in the present example embodiment, the second lubricant chamber H7 is formed when (the opening of) the concave portion formed at the front end surface of the third peripheral wall portion 241 of the rear housing 24 is covered by the fixed plate 511 of the fixed scroll 51. That is, as is the case with the first lubricant chamber H5, the second lubricant chamber H7 is formed between the fixed scroll 51 and the rear housing 24. In addition, the second lubricant chamber H7 is disposed above the first lubricant chamber H5 and is formed radially outside the discharge chamber H3 such that the second lubricant chamber H7 surrounds the discharge chamber H3 (see FIG. 2 ).

The second lubricant chamber H7 is connected to the first lubricant chamber H5 via a third orifice (a third restriction portion) OL3. In the present example embodiment, a channel formed on the front end surface of the third peripheral wall portion 241 of the rear housing 24, specifically, a narrow channel, a shallow channel, or a narrow and shallow channel that connects a circumferential end portion of the first lubricant chamber H5 and a circumferential end portion of the second lubricant chamber H7, is covered by the fixed plate 511 of the fixed scroll 51, and thereby, the third orifice OL3 is formed. That is, as is the case with the first lubricant chamber H5 and the second lubricant chamber H7, the third orifice OL3 is formed by the fixed scroll 51 and the rear housing 24. In addition, the first lubricant chamber H5 and the second lubricant chamber H7 are connected in series in a circumferential direction via the third orifice OL3.

In addition, the fixed plate 511 of the fixed scroll 51 has a lubricant return hole L7 for returning the lubricant to the space H8 near the outer end portion of the scroll unit 50, in other words, to a portion near the outer end portion (the spiral end portion) of the orbiting spiral wall 522 of the orbiting scroll 52. In the present example embodiment, the lubricant return hole L7 is formed above the discharge hole L2. In addition, the lubricant return hole L7 has one end portion that is open to the other surface of the fixed plate 511 and communicates with the second lubricant chamber H7 and has the other end portion that is open to a portion corresponding to the spiral end portion of the orbiting spiral wall 522 of the orbiting scroll 52 on the one surface of the fixed plate 511.

Next, how the gaseous refrigerant and lubricant flow in the scroll compressor 10 will be described with reference to FIGS. 1 and 3 . FIG. 3 is a block diagram illustrating how the gaseous refrigerant and lubricant flow in the scroll compressor 10. In FIG. 1 , flow of gaseous refrigerant which has not been mixed with lubricant, or flow of gaseous refrigerant from which lubricant has been separated out, is indicated by a hatched arrow; and flow of gaseous refrigerant including lubricant is indicated by a black arrow, and flow of lubricant separated out from the gaseous refrigerant is indicated by a white arrow.

As illustrated in FIGS. 1 and 3 , the low-pressure gaseous refrigerant from the refrigerant circuit flows into the intake chamber H1 via the intake port P1 and is guided to the space H8 located near the outer end portion of the scroll unit 50 via the refrigerant passage L1. After being guided to the space H8, the low-pressure gaseous refrigerant is drawn into and compressed in the compression chamber H2 of the scroll unit 50 as the orbiting scroll 52 performs its orbiting motion. The gaseous refrigerant (high-pressure gaseous refrigerant) compressed in the compression chamber H2 is discharged into the discharge chamber H3 via the discharge hole L2 (and the check valve 90) and next flows to the gas-liquid separation chamber H4 via the communication hole L3. After the gaseous refrigerant flows to the gas-liquid separation chamber H4, the lubricant contained in the gaseous refrigerant is separated from the gaseous refrigerant by the oil separator 100. Next, the gaseous refrigerant separated from the lubricant by the oil separator 100 is guided to the refrigerant circuit through the discharge port P2. In addition, the lubricant separated from the gaseous refrigerant by the oil separator 100 flows from the bottom portion of the gas-liquid separation chamber H4 through the connection passage L4 and is stored in the first lubricant chamber H5.

The first lubricant chamber H5 communicates with the discharge chamber H3 via the connection passage L4, the gas-liquid separation chamber H4, and the communication hole L3. In addition, the first lubricant chamber H5 communicates with the back pressure chamber H6 via the lubricant passage L5, and the back pressure chamber H6 communicates with the intake chamber H1 via the pressure release passage L6.

Thus, (some of) the lubricant stored in the first lubricant chamber H5 is supplied to the back pressure chamber H6 through the lubricant passage L5. Thus, the lubricant passage L5 in the present example embodiment constitutes a “first lubricant supply passage” according to the present invention. Herein, the first orifice OL1 is disposed in the lubricant passage L5. Thus, the lubricant stored in the first lubricant chamber H5 is supplied to the back pressure chamber H6, with the pressure of the lubricant being reduced from a pressure Pd in the discharge chamber H3. In addition, the second orifice OL2 is disposed in the pressure release passage L6. Thus, the flow rate of the lubricant (and/or the gaseous refrigerant) that flows from the back pressure chamber H6 to the intake chamber H1 is restricted. As a result, the pressure in the back pressure chamber H6 is maintained at a medium pressure (back pressure) Pm between a pressure Ps in the intake chamber H1 and the pressure Pd in the discharge chamber H3, and this medium pressure (back pressure) Pm presses the orbiting scroll 52 to the fixed scroll 51. That is, the back pressure chamber H6 has the back pressure Pm that presses the orbiting scroll 52 to fixed scroll 51.

In addition, the first lubricant chamber H5 communicates with the space H8 located near the outer end portion of the scroll unit 50 via the third orifice OL3, the second lubricant chamber H7, and the lubricant return hole L7. The pressure in the space H8 is the same as the pressure Ps in the intake chamber H1.

Thus, (some of) the lubricant stored in the first lubricant chamber H5 is supplied to a portion near the outer portion of the scroll unit 50 through the third orifice OL3, the second lubricant chamber H7, and the lubricant return hole L7. Therefore, in the present example embodiment, the passage formed by the third orifice OL3, the second lubricant chamber H7, and the lubricant return hole L7 constitutes a “second lubricant supply passage” according to the present invention. The pressure of the lubricant stored in the first lubricant chamber H5 is reduced as the lubricant flows through the third orifice OL3 (and the second lubricant chamber H7), and the lubricant is supplied to the portion near the outer portion of the scroll unit 50. In addition, some of the lubricant stored in the first lubricant chamber H5 is stored in the second lubricant chamber H7, and the lubricant stored in the second lubricant chamber H7 is also supplied to the portion near the outer portion of the scroll unit 50.

As described above, in the scroll compressor 10 according to the example embodiment, the lubricant separated from the gaseous refrigerant by the oil separator 100 is stored in the first lubricant chamber H5, and (some of) the lubricant in the first lubricant chamber H5 is supplied to the portion near the outer end portion of the scroll unit 50 through the second lubricant chamber H7 disposed above the first lubricant chamber H5 and connected to the first lubricant chamber H5 via the third orifice OL3 and through the lubricant return hole L7 formed in the fixed plate 511 of the fixed scroll 51. That is, the scroll compressor 10 supplies the lubricant in the first lubricant chamber H5 upward to the portion near the outer edge portion of the scroll unit 50 while reducing the pressure of the lubricant. Thus, the gaseous refrigerant drawn into the scroll unit 50 can be stably mixed with an appropriate amount of lubricant. That is, shortage of lubrication for sliding portions of a scroll unit can be prevented.

In particular, one end portion of the lubricant return hole L7 is open to the other surface of the fixed plate 511 and communicates with the second lubricant chamber H7, and the other end portion of the lubricant return hole L7 is open to a portion corresponding to the spiral end portion of the orbiting spiral wall 522 of the orbiting scroll 52 on the one surface of the fixed plate 511. Thus, the lubricant can be supplied to an area in which the compression chamber H2 is formed and can be mixed with the gaseous refrigerant drawn into the scroll unit 50 without fail. As a result, shortage of lubrication for a slide member of a scroll unit can be prevented more effectively.

In addition, the second lubricant chamber H7 is formed radially outside the discharge chamber H3 such that the second lubricant chamber H7 surrounds the discharge chamber H3, and the first lubricant chamber H5 and the second lubricant chamber H7 are connected in series in a circumferential direction via the third orifice OL3. In addition, the first lubricant chamber H5, the second lubricant chamber H7, and the third orifice OL3 are formed by (the fixed plate 511 of) the fixed scroll 51 and the rear housing 24. Thus, it is possible to realize a function of supplying some of the lubricant in the first lubricant chamber H5 to the portion near the outer portion of the scroll unit 50 while reducing the pressure of the lubricant, without increasing the size of the scroll compressor 10 or the number of components. Furthermore, it is possible to realize a function of supplying some of the lubricant in the first lubricant chamber H5 to the spiral end portion of the orbiting spiral wall 522 of the orbiting scroll 52 while reducing the pressure of the lubricant.

Although an example embodiment of the present invention has thus been described, the present invention is not limited to the above example embodiment. Further variations and modifications can of course be made based on the basic technical concepts of the present invention.

REFERENCE SYMBOL LIST

10 scroll compressor

20 housing

21 front housing

23 center housing

24 rear housing (housing member)

50 scroll unit

51 fixed scroll

52 orbiting scroll

100 oil separator

511 fixed plate

512 fixed spiral wall

521 orbiting plate

522 orbiting spiral wall

H1 intake chamber

H2 compression chamber

H3 discharge chamber

H4 gas-liquid separation chamber

H5 first lubricant chamber

H6 back pressure chamber

H7 second lubricant chamber

L1 refrigerant passage

L2 discharge hole

L3 communication hole

L4 connection passage

L5 lubricant passage (first lubricant supply passage)

L6 pressure release passage

L7 lubricant return hole

OL1 to 3 orifice 

1. A scroll compressor having a housing in which a scroll unit including a fixed scroll and an orbiting scroll that face each other is disposed, the housing including a discharge chamber into which gaseous refrigerant compressed by the scroll unit is discharged, the scroll compressor comprising: an oil separator that separates lubricant from the gaseous refrigerant discharged into the discharge chamber; a first lubricant chamber that stores the lubricant separated by the oil separator; a back pressure chamber that is formed on a back surface side of the orbiting scroll; a first lubricant supply passage for supplying the lubricant in the first lubricant chamber to the back pressure chamber; and a second lubricant supply passage for supplying the lubricant in the first lubricant chamber to a portion near an outer end portion of the scroll unit, wherein the second lubricant supply passage is formed as a passage that allows the lubricant in the first lubricant chamber to flow through the second lubricant chamber disposed above the first lubricant chamber and connected to the first lubricant chamber via an orifice.
 2. The scroll compressor according to claim 1, wherein the second lubricant supply passage is formed as a passage for allowing the lubricant that has passed through the second lubricant chamber or lubricant that is stored in the second lubricant chamber to flow through a lubricant return hole formed in the fixed scroll.
 3. The scroll compressor according to claim 2, wherein the lubricant return hole is formed above a discharge hole through which the gaseous refrigerant compressed by the scroll unit is discharged to the discharge chamber.
 4. The scroll compressor according to claim 2, wherein the fixed scroll includes a fixed plate and a fixed spiral wall that is erected on one surface of the fixed plate, wherein the orbiting scroll includes an orbiting plate and an orbiting spiral wall that is erected on one surface of the orbiting plate, wherein the fixed scroll and the orbiting scroll are disposed such that the fixed spiral wall and the orbiting spiral wall engage with each other, and wherein one end of the lubricant return hole is open to another surface of the fixed plate and communicates with the second lubricant chamber, and another end of the lubricant return hole is open to a portion corresponding to a spiral end portion of the orbiting spiral wall on the one surface of the fixed plate.
 5. The scroll compressor according to claim 1, wherein the second lubricant chamber is formed radially outside the discharge chamber such that the second lubricant chamber surrounds the discharge chamber.
 6. The scroll compressor according to claim 5, wherein the first lubricant chamber and the second lubricant chamber are connected in series in in a circumferential direction via the orifice.
 7. The scroll compressor according to claim 1, wherein the first lubricant chamber, the second lubricant chamber, and the orifice are formed by the fixed scroll and a housing member constituting the housing.
 8. The scroll compressor according to claim 3, wherein the fixed scroll includes a fixed plate and a fixed spiral wall that is erected on one surface of the fixed plate, wherein the orbiting scroll includes an orbiting plate and an orbiting spiral wall that is erected on one surface of the orbiting plate, wherein the fixed scroll and the orbiting scroll are disposed such that the fixed spiral wall and the orbiting spiral wall engage with each other, and wherein one end of the lubricant return hole is open to another surface of the fixed plate and communicates with the second lubricant chamber, and another end of the lubricant return hole is open to a portion corresponding to a spiral end portion of the orbiting spiral wall on the one surface of the fixed plate.
 9. The scroll compressor according to claim 2, wherein the second lubricant chamber is formed radially outside the discharge chamber such that the second lubricant chamber surrounds the discharge chamber.
 10. The scroll compressor according to claim 3, wherein the second lubricant chamber is formed radially outside the discharge chamber such that the second lubricant chamber surrounds the discharge chamber.
 11. The scroll compressor according to claim 4, wherein the second lubricant chamber is formed radially outside the discharge chamber such that the second lubricant chamber surrounds the discharge chamber.
 12. The scroll compressor according to claim 2, wherein the first lubricant chamber, the second lubricant chamber, and the orifice are formed by the fixed scroll and a housing member constituting the housing.
 13. The scroll compressor according to claim 3, wherein the first lubricant chamber, the second lubricant chamber, and the orifice are formed by the fixed scroll and a housing member constituting the housing.
 14. The scroll compressor according to claim 4, wherein the first lubricant chamber, the second lubricant chamber, and the orifice are formed by the fixed scroll and a housing member constituting the housing.
 15. The scroll compressor according to claim 5, wherein the first lubricant chamber, the second lubricant chamber, and the orifice are formed by the fixed scroll and a housing member constituting the housing.
 16. The scroll compressor according to claim 6, wherein the first lubricant chamber, the second lubricant chamber, and the orifice are formed by the fixed scroll and a housing member constituting the housing. 